Good Morning and welcome! I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
I am so sorry to hear that Tucker is not feeling well. In most cases such as this, the dogs ingest something that has caused a minor digestive disturbance that you may not even be aware of. The treatment for this is as follows:
Fast Tucker for 12-24 hrs which he is doing himself to allow the digestive tract to calm down and heal.
Give him Pepcid AC or Famotidine at 0.5 mg per pound every 8 hrs. That can be purchased over the counter at the pharmacy.
Give only small amounts of water during the fast or ice cubes
After the fast, feed rice and boiled chicken (2/1)
If the lethargy has resolved, then wean Tucker back onto regular food. If the this persists especially during the fast, take your dog to your vet for an exam and lab work to determine the cause for this. This is extremely important since this can cause dehydration or other more serious concerns such as an obstruction that may require more intensive treatment.
Does that make sense to you?
Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please REPLY so I can clarify for you.
Sincerely, ***** *****